Russia is rejecting American evidence of chemical weapons use in Syria as "inconclusive" and urging the United States to declassify all of its intelligence.

"What we were shown before and recently by our American partners, as well as by the British and French, does not convince us at all," Sergei Lavrov said, according to Interfax, in Russia's most direct rebuke yet to the American claims.

"There are no facts, there is simply talk about what we definitely know. But when you ask for more detailed evidence, they say that it is all classified, therefore it cannot be shown to us. This means there are no such facts to encourage international cooperation," the minister told a group of students this morning.

On Friday, the Obama administration published evidence, including wiretaps, it says proves forces loyal to Syrian President Bashar al-Assad used chemical weapons in an attack on August 21 near Damascus that killed 1,492 people including hundreds of children. President Obama has decided the attack warrants a military response by the United States, but will seek authorization from Congress first.

"We now have evidence from hair and blood samples from first responders in East Damascus, the people who came to help, we have signatures of Sarin in their hair and blood samples, so the case is growing stronger by the day," Kerry told ABC's George Stephanopoulos on 'This Week.'

Syrian authorities have denied the claims. The US ambassador to Russia Michael McFaul presented the evidence directly to the Russian Foreign Ministry on Saturday. Russian officials have dismissed it as long on claims yet short on specifics.

"Yes, we were shown certain pieces of evidence that did not contain anything concrete - neither geographical locations, nor names, nor evidence that samples had been taken by professionals. Nor did they comment on the fact that numerous experts have serious doubts regarding the video footage circulating on the Internet," Lavrov said, according to Interfax.

Lavrov urged the US to declassify all the evidence.

"If there truly is top secret information available, the veil should be lifted. This is a question of war and peace. To continue this game of secrecy is simply inappropriate," he said.

Meanwhile, Interfax quoted an unnamed Russian military official saying that a Russian spy ship called the Priazovye had been deployed to the eastern Mediterranean on "very short notice" to monitor the escalating situation. The United States has bulked up its naval presence in the region in preparation for a possible strike in Syria.

"The Priazovye departed to the designated area in the eastern sector of the Mediterranean Sea on Sunday evening. The crew are to perform their direct duties - to collect tactical information in the area of escalated conflict," the source told Interfax.